Does it support nested objects and arrays of objects?

Yes, deeply nested structures are automatically decoupled into separate, clean interfaces.

How does it handle null or mixed-type values in arrays?

It intelligently infers union types (e.g. `string | null` or `number[]`).

JSON to TypeScript Interface

Root Type Name:

Add “export” keyword

JSON Input Payload

Generated TypeScript Interfaces

export interface UserResponse {
  id: string;
  name: string;
  email: string;
  role: string;
  active: boolean;
  profile: Profile;
  roles: string[];
  projects: Project[];
}

export interface Project {
  id: string;
  title: string;
  stars: number;
  isOpenSource: boolean;
}

export interface Profile {
  avatarUrl: string;
  bio: string;
  reputation: number;
}

How to generate TypeScript types from JSON

1Paste any valid JSON payload into the left input pane.
2Choose your root interface name (e.g. `UserResponse` or `RootObject`).
3Copy the generated TypeScript interface declarations directly into your `.ts` file.

Full-Stack Type Safety

Accelerate frontend development by automatically inferring accurate TypeScript contracts from backend REST and GraphQL API responses.

Architecture & Privacy

Recursive structural type inference: Automatically extracts nested sub-interfaces for child objects and arrays.
Identifier key escaping: Reserved characters and dashes in JSON keys are safely quoted (e.g., "x-api-key": string;).
Zero-network isolation: Ideal for transforming proprietary backend responses and confidential microservice payloads.

Frequently Asked Questions

Related Developer Utilities

Essential

JSON Formatter & Validator

Format, validate, repair, and minify JSON payloads with syntax highlighting

Launch tool→

URL Encoder & Decoder

Encode and decode query strings, URI components, and inspect query params

Launch tool→

HTML Entity Encoder / Decoder

Escape and unescape special HTML characters to prevent XSS issues

Launch tool→